Life Cycle assessment-based analysis of Environmental Impacts and Mitigation Strategies for Enzyme-Induced Calcite Precipitation
전주기평가(LCA) 기반 효소유도 탄산칼슘 침전(EICP) 기술의 환경영향 및 저감 전략에 관한 연구
- 주제(키워드) Biopolymer , Biopolymer-based Soil Treatment , Enzyme-Induced Calcite Precipitation , BPST , EICP , LCA
- 주제(DDC) 690
- 발행기관 아주대학교 일반대학원
- 지도교수 장일한
- 발행년도 2026
- 학위수여년월 2026. 2
- 학위명 석사
- 학과 및 전공 일반대학원 건설시스템공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000036006
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Despite their superior mechanical performance, cement-based soil stabilization methods are limited in terms of sustainability due to high CO2 emissions and energy consumption. To address these issues, sustainable soil stabilization methods, such as Biopolymer-based Soil Treatment (BPST) and Enzyme-induced Calcite Precipitation (EICP), have recently been investigated. However, these methods face limitations, including reduced durability in wet conditions, non-uniform calcite precipitation, and the emission of nitrogenous byproducts. To mitigate these drawbacks, this study proposes Biopolymer-assisted EICP (BAE), a hybrid approach combining BPST and EICP, and comprehensively evaluates its mechanical performance and environmental impact. Mechanical performance was assessed through Unconfined Compressive Strength (UCS) tests, while chemical and microstructural characteristics were analyzed by measuring the pH of the effluent and employing SEM-EDS. Furthermore, a Life Cycle Assessment (LCA) was conducted for Soil Cement (SC), BPST, EICP, and BAE, with the treatment of 1 m³ of soil defined as the functional unit. This LCA quantitatively compared the global warming potential (GWP), acidification potential (AP), and eutrophication potential (EP) across these methods. The research findings indicate that BAE exhibited more homogeneous strength development properties compared to both EICP and BPST. It also consistently achieved target strengths with relatively fewer treatment repetitions. SEM-EDS analysis revealed that BAE facilitated the formation of calcite precipitates alongside biofilms and bridges formed by biopolymers. Moreover, its negatively charged properties were found to adsorb NH4 +. Consequently, the pH of the effluent after BAE treatment was closer to neutral compared to EICP. LCA results showed that SC registered high values across all environmental impact categories. While EICP demonstrated reduced GWP compared to SC, its AP and EP significantly increased due to nitrogenous byproducts. In contrast, BAE significantly reduced GWP, AP, and EP compared to EICP. This quantitatively validates the effectiveness of the experimentally confirmed NH4 + adsorption in mitigating environmental impacts. This study presents BAE as a hybrid soil stabilization method capable of simultaneously achieving both mechanical performance and sustainability from both experimental and environmental perspectives.
more목차
CHAPTER 1. INTRODUCTION 1
1.1 Background 1
1.2 Organization 5
CHAPTER 2. LITERATURE REVIEW 8
2.1 Introduction 8
2.2 Biopolymer-based Soil Treatment (BPST) 11
2.2.1 Overview of Xanthan gum biopolymer 11
2.2.2 Strengths 14
2.2.3 Weaknesses 16
2.3 Enzyme-Induced Calcite Precipitation (EICP) 17
2.3.1 Overview of EICP 17
2.3.2 Strengths 17
2.3.3 Weaknesses 19
2.4 Life Cycle Assessment 20
2.4.1 Fundamental of Life Cycle Assessment 20
2.4.2 Application of LCA in Soil Stabilization Studies 22
2.5 Biopolymer-assisted EICP (BAE) for Soil Stabilization 26
2.5.1 Motivation for BAE 26
2.5.2 Research Gap 27
2.6 Summary 29
CHAPTER 3. MECHANICAL AND CHEMICAL PERFORMANCE EVALUATION OF SOIL STABILIZATION METHODS 30
3.1 Introduction 30
3.2 Materials and Methods 34
3.2.1 Soil Properties 34
3.2.2 Jackbean Crude Urease Manufacturing 35
3.2.3 Soil specimen preparation. 36
3.2.4 Unconfined Compressive Test 39
3.2.5 Chemical Characterization analysis using pH Measurement of Effluent 39
3.2.6 Microstructural Characterization analysis using SEM-EDS 40
3.3 Results and Discussions 41
3.3.1 Unconfined Compressive Strengths of Soil Stabilization Methods 41
3.3.2 pH measurement of Effluent 51
3.3.3 Chemical and Microstructural Characterization 52
3.4 Conclusions 54
CHAPTER 4. LIFE CYCLE ASSESSMENT OF SOIL STABILIZATION METHODS FOR ENVIRONMENTAL IMPACT EVALUATION 57
4.1 Introduction 57
4.2 Methodology 59
4.2.1 Case scenarios 60
4.2.2 Goal and Scope 61
4.2.3 System Definitions and Assumptions 62
4.2.4 Life Cycle Inventory 64
4.2.5 Life Cycle Impact Assessment 71
4.3 Interpretation of Environmental Assessment Case Scenarios Results 73
4.3.1 Global Warming Potential 73
4.3.2 Acidification Potential 74
4.3.3 Eutrophication Potential 76
4.4 Conclusions 77
CHAPTER 5. Conclusions and Future Works 78
5.1 Summary and Conclusion 78
5.2 Limitations and Further Studies 79
REFERENCES 82
요약문 93
